Carnitine palmitoyltransferase

Function

Carnitine palmitoyltransferase (CPT I and CPT II) are involved in the transport of long-chain fatty acids into the mitochondria where they are oxidized. Fatty acids form a conjugate with CoA before being oxidized in the mitochondria. However, the CoA-long-chain fatty acid conjugates can not diffuse into the mitochondria.

• CPT I is a membrane protein which substitutes the CoA in the long-chain fatty acids by carnitine. After entering the mitochondria.
  
• CPT II exchanges the carnitine by CoA, enabling the oxidation of the long-chain fatty acids.

Disease

CPT I deficiency prevents the body from using certain fats for energy, particularly during fasting. It is associated with encephalopathy, seizures and unexpected infancy death. CPT I is important in fatty acid disorders like diabetes.

Structural highlights

CPT I contains an extra ca. 160 amino acids domain at its N terminal. Substrate analog interacts with CPT II 2rcu in a large tunnel with its hydrophilic head group situated at the tunnel center and the alkyl part occupying the hydrophobic part of the tunnel.